Methods - Bias Adjustment
Unlike GHCN-Monthly , GHCN-Daily does not contain adjustments for biases resulting from historical changes in instrumentation and observing practices. It should be noted that historically (and in general), the stations providing daily summaries for the dataset were not managed to meet the all of the desired standards for climate monitoring. Rather, the stations were deployed to meet the demands of agriculture, hydrology, weather forecasting, aviation etc. Because GHCN-Daily has not been homogenized to account for artifacts associated with the various eras in reporting practice at any particular station (i.e., for changes in systematic bias), users should consider whether the potential for changes in systematic bias might be important to their application. In addition, GHCN-Daily and GHCN-Monthly are not currently internally consistent (i.e., GHCN-Monthly is not necessarily derived from the data in GHCN-Daily); however, GHCN-Daily is anticipated to be a major source of future updates to GHCN-Monthly.